1. Field of the Invention
This invention relates to a slide-action switch used for example in connection with a door of a refrigerator and, more broadly, to an improvement on a switch of the type wherein a movable contact slidingly engages and disengages with a fixed contact.
2. Description of the Prior Art
FIGS. 2 and 3 show a conventional switch of the above type. In these drawings, reference numeral 1 indicates a switch body which is provided with a control knob 2 urged outwardly by a spring (not shown). This control knob 2 has a slide 6 movable together therewith, which supports a movable terminal 3. The end of this movable terminal 3 is bent arcwise to form a movable contact 3a.
Reference numeral 4 indicates an insulating wafer of the switch body 1, which has a fixed terminal 5 secured thereon. The movable contact 3a presses resiliently against the surface of the wafer 4. As the control knob 2 is pushed into the switch body, the movable contact 3a slides on the wafer 4 and comes into contact with a fixed contact region of the fixed terminal 5 thereby forming an electrical connection between the fixed terminal 5 and the movable terminal 3.
As the movable contact 3a slides against the contact region of the fixed terminal 5, it wipes away dirt and thus assures a good electrical connection. However in the foreging conventional switch, metal on the surface of each terminal is rubbed off and it forms a contaminating powder which remains on the surface of the insulating wafer 4 and contaminates a region 4a of the wafer which is supposed to act as an insulating barrier between the fixed terminal 5 and the movable contact 3a when the latter is slid away from the former. Due to this contamination, the conventional prior art switch loses its ability to resist high voltage. In its open-circuit state, the switch cannot prevent a high voltage arc from crossing the powder contaminated region on the wafer surface; so the lifetime of the switch and the appliance in which it is installed becomes prematurely shortened by powder generated from its sliding metal contacts.